Abstract 1397: Metabolic CRISPR-Cas9 screening identifies loss of mitochondriaGene Min triple-negative breast cancer to promote lung metastasis via immune modulation

Abstract Triple-negative breast cancer (TNBC) is a heterogenous breast cancer characterized by an aggressive phenotype and high risk of metastatic occurrence. Metastasis is a multifaceted process that involves metabolic reprogramming, selection, and adaptation. Although studies have shown that alterations of metabolic processes can influence TNBC phenotype and sensitivity to treatments, less is known about how changes in metabolic enzymes in the tumor cells affect crosstalk between tumor and immune cells during metastasis. Here, we performed a high-throughput CRISPR-Cas9 screening of metabolic genes in an orthotopic basal-like mammary carcinoma 4T1 mouse model to identify key metabolic enzymes in the tumor cells that are associated with TNBC lung metastasis by affecting the tumor microenvironment (TME). The CRISPR-Cas9 screening showed an enrichment of sgRNA for mitochondria Gene M in the metastasized lungs of wild-type mice but not Rag1−/− mice, indicating that loss of Gene M could modulate adaptive immune cells in the TME or distant organs to promote 4T1 lung metastasis. Further pilot experiments revealed that loss of Gene M in 4T1 cells increased murine basal-like carcinoma lung metastasis in vivo and decreased population of B cells, CD4+ T cells, M2 macrophages, monocytes, and CXCR2+ neutrophils in the metastasized lungs without affecting the growth rate of the primary tumors. Overall, our preliminary results demonstrated that Gene M deficiency in 4T1 cells affects immune cell profile and drives lung metastasis of murine basal-like carcinoma cells, but the molecular and cellular mechanisms by which loss of Gene M grant tumor cells with metastatic advantage requires further investigation. Citation Format: Shu-Ting Chou, Xiaoyong Wang, Deanna N. Edwards, Jin Chen. Metabolic CRISPR-Cas9 screening identifies loss of mitochondriaGene Min triple-negative breast cancer to promote lung metastasis via immune modulation abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 1397.